Corn protein printing ink and ink base



Patented Jan. 4, 1944 Harry M.1Weber, Chicago, 111., assignor to American Maize-Products Company, New York, N. 2.. a corporation of Maine No Drawing.

Claims.

The present invention relates generally to protein printinginks and printing ink bases containg water in the vehicle, and in particular to 'those having corn protein as an essential ingredient of the vehicle, body or hinder thereof.

- adherent starch, fiber and corn oil. Asordinarily The body of printing inks :mustxbe such that the ink'compositions or ink bases are stable'for long'periods of time, and such that they do not alter chemically the pigments or :COIOIS used therein. The links must be such that they apply readily and'adhere wellto paper. Applied ink coats are preferred which dry rapidly to a nontacky surface, thus avoiding off-setting; Dried ink coats which are water-resistant, non-bleeding,, and non-smudging are also important'obe iec'tives.- Another important-objective :in compounding inks is to produceone which-may be contacted with steam or heat to aid in setting 'theink and income cases to drive oil more quickly volatile solvent ingredients.

Another major requirement in inks is that they must not dry to insoluble or non-dispersible products on the movingparts or type of the press or in other words must remain open. Hereto- I fore, this requirement has been an obstacle in the use of proteins in inks. For example, in the practical use of some inks, such as news inks, they are worked over and over on a series of rolls, while exposed to th air, before they reach the impression type. Such inks must remain free or open, be'non-skinning, and retain body and pigment during this period, Yet provide,

when applied, a reasonably quick-drying ink.

I have found that corn protein has inherent "properties which enables it to be compounded to provide a vehicle, body 'or binder for inks or ink bases to meet some or all of these desirableconditions. I have further found that corn protein may be compounded into inks suitable for news, rotogravure or planograph printing, and for abserption, heat and flash-dry application, to produce in all cases non-ofl-setting and Smudge- Application February 17,1941, I

semi No. 379,200

he corn refining industry and may be impure with obtained, gluten runs 50% to 60% protein. When further purified .by the -removal of starch to form a starch-free product, it, canfbe made to contain 70% to 80% protein, consisting of all the water-insoluble proteins qfjcorn, including the prolamine'zein, together with 8 toiqflbof oily material, 4%"to 6% fiber, 1% 0. 3% ash,

and a residue of moisture. The full corn prqtfiin is roughly halfrzein, thesremainder beinga xiii-xi tureof glutelin and globulin. Broadly, corn pro-- tein may be the protein product from whichfihe, alcohol soluble prolamine zein has been iarglyl removed.

Zein is defined as the alcoholsoluble content,

and it is soluble "in a large number 01' organic solvents and mixtures, witlrand without water as a solvent ingredient. The other proteins are not likewise soluble in organic solvents. the said proteins are dispersible in dilute solutions, of the strong-alkalis. 'lhe present invention contemplates viscous .or liquid dispersions of corn except where differentiation is indicated.

proof copy, and when desired, non -bleeding and water-resistant copy. I, 1 Eurthermore, I have found that com protein may be compounded into inks of which the liquid vehicle may vary from an entirely aqueous one toa substantially non-aqueous one. Thus, corn protein may be utilized to form both low-cost inks, such as news inks, and relatively more expensive inks' which fall within the price range of inks now in common use, such as the varnishbase and cellulose-derivative-base inks. i I

Corn protein is a product derived from corn in the manufacture of corn starch from corn Whether the ink compositions of the present invention are entirely aqueous or not, or have zein alone, or all or apart of the corn protein, the characteristics of the printed copy as to nontackiness after initial drying, zoodadherenceto paper, non-smudgin-g, and when desired, n'onbleeding and water-resistant, are essentially the same when they are applied and'dried either by the absorptive capacity of the papeiyas innews ink, or by the evaporative drying of the printed surface,- as in rotogravure work, or by force drying by the use of a high (1 8 186 of heat applied for a short period. t

The ink bases or inks, may fall anywhere in the range ofv composition wherein the liquid vehicle is entirely water at one extreme, or substantially anhydrous at the other extreme. Examples within these ranges are given hereinafter,

but it is first necessary to state that the methods;

of dispersing the corn protein may difier injthese extremes. Thus, in the extreme case oi all water, the dispersion of corn protein is 1 effected. by the action of alkaline solutions. In the other exltreme, where complete dispersion may be'eflected in the absence of alkali, an organic solvent or mixed solvent for zein is employed and the pro-- tein for dispersion by solution must be the zein;

However, in such case, if the non-zein protein protein, and the terms solution or dispersion are .used interchangeably in the following'description,

,content is presentpit a iinely divid I suspended form where it may function ically as tiller. Such dilermay bodysd with a rein diseolved'in a; solvent for min; the presence in m'v, isl sa cus, mac. have-described the dis- ;"solvingofseindn a nein'solvent. such as 96% by ;-.o i 'alkalijin'an solventmay em- ;res swflsew sem n copending application, Serial No. 280,112,

volume ethyl alcohol, denatured. or not, and furv therthe dissolution of shellac,- l'ceinor. other in such solution, with'or without "plasticizer'sjlorthc mired solid content,' a'nd the" of such-as printing inkbases. In such thefaicina'ml! f'to forinasolid-sclution, and then the solid solu tion'mayf'be cut" with a solvent. 1.1n my earlier 1 A applieatiom'fleiriallla umo'l iiiedbeccmber 23; 1938, which is'a continuation input of my earlier application,,Seria'l-Ho. l24,4dl, iiled February 0, 1937,11 describe the directsolution of in a solvent for sein, and then additicn of s -sheliac, or of a solution of'shellac, and further disclose dissolvin both aein and shellac together 1 in a mutual solvent. in'each case with or without so plasticiser, to form' acoating composition of a'' w p character when initially dry. I a

ever, for economic reasons, in my preferred compositions, the 'i'uli corn'prote'inis used and it is o be understood that thejsein component-of it Qwiththe ideas set forth in my copendmg awn maybe in solution in a aeinfsolvent, while the non-zeln component mayvbe suspended u filler,

- or be dispersedin a conditioned acid, neutralor alkaline aqueous medium, which condition may be plished by are further characterized by the fact thatalkali.

eifected after the-dispersion is originally accom a suitable alkaline aqueous medium. v

/ alltotidiepcrsimt f The corn protein is diiiicult to dispcrse with- 1 with avoidance of decomposition, as it requires solutions. of pH of 1110 or higher for complete'dlspersion; Itis common to disperse it by'u'se of 5% of its weight 01 caustic soda.

-' Such strong alkali solutions of the proteins of a.

pH above lip-generally. have a decomposing eflcct on corn protein and produce protein products which blacken and readily putrefy on storage of attempted ink bases produced therefrom. Therefore, dispersion is preferably eflected by dispersing conditions which avoid pH values that lead to the formation of such degradation products or at pH values under 10.0.

The corn protein dispersions of myinvention dispersions may. be reduced in pH to a pH below necessary or used for'eflccti'ng dispersion, -.-and yet"remain stable against precipitation of theprotein. Accordingly. the preferred inks and ink bases having.alkali-dispersed protein are formed by first eflecting dispersion at a relatively higher pH and then reducing the pH to near neutral, or either just above or just below pH of 'l. This has the distinct advantage that .plsments.

.ooior, and other materials maybe added to a near-neutral base, without danger of alterinl the added pig'mentinl ,Plrticles.

persed when rubbed while wet'or moist. Bleed- -ing can be eifected where the ink retains elements'which impart to it a high alkaline dis- ,persingpH to permit redisp'ersion. It is a characteristic or the present'corn protein inkcompositions, that when applied they have a pH which is lowerv than the minimum dispersing pH r a simple caustic alkali soiutiom Good ad- 7 herence and high binding power are eflected by avoidance of conditions which permit the dis- -norma l"acidity;.oi unsised paper, coated paper. and sizedpaper, .Corn protein dispersions pro- ,duced by alkali-dispersion tendnormally to pre- "cipitate at a- DH. which may be encountered in papers? "This is'avoided in the present invention by employing dispersing gents that serve during the period of application.

Another ieature oi the invention which may be t v.. tiona l th'-' a ti Wmoumy belempl. I. printing I Op 116' emp oyed is e presence of wet ng f -:.',zein may. be dksolvedl in suitable solvents or mixtures ntsolvents. whichare. either'more or lessanhydrous than 95% ethyl alcohol. How-v tion, but it also may be added prior to dispersion as a wetting or as an acid to form a wetting agent which also facilitates dispersion, in accordance cation, Serial -No. 326,621, flied March 29, 1940, referring to dispersion of corn protein for sizing paper. A further feature of the invention is the formation of such a wetting agent as a product solution having thchigh pH required to effect dispersion. v

Inorganic as well as organic wetting agents may be employed. suitableincrganic wetting agents are alkali-metal salts of the various acids of phatc, and sodium pyrophosphate. They act also as buffers. When'present 'suchinorganic wetting agents are particularly active in increasing the adherence of the corn protein dispersions to solids in general, and as inks, to paper and coated papers, and other products to which ink is app ied,

., cipita'tion to a non-gelatinous form applies either to the inks under this invention which have alkali dispersed' protein, or to zein dispersed by solution in a zein'soivent. In any casc, however, whether or; not there is zeln solution in the ink composition, the'presence of wetting agent in the ink increases adherence. The prevention of precipitation by the paper or other base to be printed,

the binding of the ink together so that it dries in These properties ,of mycorn protein dispersions are relstedtothe ultimate ink coat. 'The ability" of the deposited dried-ink to withstand smudsins f is dependent upon the adherence of the ink to i the sheet, and theinternsl binding-properties of the printed ink. Bleeding or the ink is occasioned.- by the property of the dried'ink 'tobe-redispersed protein of the "being precipitated to a non-gelatinouriorm in the applied ink prior p to drying. This form might-be ihduced'by the to bufier the ink to avoid'such ..a-- precipitation.

of, neutralization by adding an appropriate acid, such as rosin, to reduce the'pH oi the alkaline phosphorus,[examplesv being sodium metaphos This above-mentioned undesired type of preof alkali-dispersed protein in the ink, improves to make inks. in -the inknthe solvent may w vmmmmm mr diii'erent conditions. .Also the fled in many ways :bymineral non-dryinaioils; drying oilspbitumenl.

ypresent in solvents may working it priorto application; it after application.

be used to dry anapplie given by weight;

. I 'A'hard tough solid solution is I rosin, and iscommoniy referred was aglyceride the monoliydric alcoh or the zein during amass-saws,

inks'mayzbermodi oils, veletebie oils.- ietty acids,

waxes. resins. esters, others. plastieisersassent;

:be ehosento sivea spplyinginks un and agents which remain permanently in the ink." and theillike. ".Alloi these materialsare readily dis persible in persions or the proteins. Where sein solution theiink,1ow-boilingand high-boiling be variously used to aflect. or-pre- 1 volatile character of s the ink, ior

th .alkalinereactin: solutions rd!!! determine the and vtor dryl s Where steam or d ink. it may so alter the solvent as to destroy its result that the ink. is "deposited. may bereferred to to-b'e' distinguished Although this from the-precipitation to a non-gelatinous Iiorm as applied to "solutions or alkali-dispersionsofthe protein; a

' Where corn protein containinl'icorn oil or. other added saponifiable oil is mayprovide wetting agentof the oil to form soap; whichv buffer-in applied simpl I taneously with saponiiication of an oil; an amount of glycerine is formed which actsas a softening dispersed in alkali it by partial or -co1n plete saponification becomes active as a for the dried ink.

agent'or plasticizer solvent power, with the,

selatinous atroom The following examples, whereinparts are i cationwith heat from alcohol) and the abietie illustrate theinvention;

formed by masti- 40 parts by Weight of z'eingum. Esterjg m is a par-' of abietic acid; the latter being a rnono-basic 6r.- ganic acid. The ester. gum of commerce has it measurable acid-number, showing it to be an in-(.

completely reactedester. tion makes an excellent cut with 400 to 700 parts This solid comp'osia high-boiling solvent,

such as the glycols and ethylene g'lyools" or their be cut by 5% methanol- Example 2 e 1 product may hol, such as stable solutions at 100 parts ofcommercial Iull co austic soda, andheated to about. 12.5. Tlien"' added, reducing thepH; dium abietate.- Carbon black'i amount from 100 to 180 parts ismilledginto the P mm 1111! base en:

190 proof ethyl alcohol," (grain or denatured) tor intaslio printing. A istender'may be used in'rnakingthe" solid solution."

The'distender may be 1 thus dispersed at a pH of parts 01 woodrosin are to 8.3,'by forming so:

.pigmentuini the' v taming 75%"proteinis added to 360 partsoiawater containing 5 parts oi 0 "165 F. The protein is dispersion, with addition of water of .abouti260 I to 550 parts to make aj liquid dispersion. I Used. as an ink on paper this provides asmudge-proot printed surface. Such a-compositionis subject too long la periodtemperature) owing to to 'pu'trefaction it stored for (a week to 10 days at room the adverse action of the strong dispersing alkali maintaining mains dispersed in the resultinl ls satisfactory go' mass heated or the protein."

- or filler ma be p rt's, fliash'Qdry 111x250 parts of" the diaper-- sl'on' offExamplej 1 protein eot'rfatty acids, rnprotein eon-r 23 perfect caustic soda. The mixturev is slowly 'heated to 185 F. This action completely saponi- .nedthe rosin and disper i d the protein to a mass tempra'ture with a pH of 8.9. Then .by adding 50'' parts of rosin-meanwhile I V the temperature ot the mass at 185 F. and mechanically agitating. the protein :re-

mass at i-1 7.2.

To this 1000: parts of carbon black is added, and

diluted with water tothe-point where it can be app d'by mean oi'rollsandused as anink. .1. wim

broadly precipitation. it is 2 The Pr 'ra fl dm *Eiempl' ails-not suitable for u e on all present-day presses asan inkgbeing'fitoo *shortjior such a method 011 application.

Y "ordinary mineral oil newsginhlfor which, it

corn, protein r as. "ru is 'anink. base, into milled.

Example 6 "is diluted .with so pm; for

1. part iotlaurici aci'dthe pH wate'r'. 1; ray adding 1 is. reduced to 6.9.

' subjecte ro'r' '..'.-Il.. i m a rotogravure ink, ,500 parts'oi iuli corn -havin'g'l5'% protein and .0% corn oil and 100 parts otrosln, 980 parts-oi! iso- .propyl alcohol or 99% 520 partso! water. are made into parts of causticsodaheated to 155 1 a-slurry. is addedxandthemixture 60 F. or a temperature below-the as boiling point of the alcohol mixture. Y I lsaponiiie's the corn oil, fatty acids-and and completely disperses the protein. fi o ink-base are added 360 partsf'oidcolor', suchas Milori blue, 192 parts oiv Santicizer 8; 360Yp'arts 70 ot- 99% (by volume) isopropyl alcohol," and .120

rotogravure press;

dilution of the press and for In some instances iurther ink is 75 .isopropyl alcohol is used.

o are suspended in a slurry'aoi 1500 parts oiwater. and

i llto' io parts'joi'thefsolids oi the a 'bas'e,-prior to the .heutralization-stepof. addins the 'rosin innxa le-s; lengthens the re 1 .isultins' inkfgiving it the characteristics otlanf I to" given smudge-prooiand'sub I stantially non-bleeding. rinted'jsu g Q :1

jcontainingiwqt' .4 or .diethylene' glycol; and 600 parts of water,v are mixed in a mechanical miiger. Then-1% .parts or peroxideis added to" g Y reduce'the coloringmaterial-present lnthidprod not, and "mixing; iscontinued tori samlm m- Then .14 partsof caustic soda are added and-the to .150-169F. to street dispersion},

The-resulting mass has ajpH which pigment flfi color such as lvlilorigblue milledinto-the substantially q'jneutral base. when printed onsized paper, and a short-time or 0.01'td 0.002 minute" SOD-900 1" the ink iszsii'iudd pifoof by volume) strenxth',' and parts of water, to produce an ink suitable fora I desirable to adaptit tot-he this purpose (by weight) v a pH 01' 7.2 by neutralization with rosin Icons? 8 exsaurbple, the pH of ink m This was reduced to to a P1! of color, I60 parts 01 this color Inthe iorelo l v duced is about 8.5 to

017.2 before the addition peacock blue, in order that the tint oi should be unaflected.

Parts by weight Dibutyl tartrate 25-35 Denatured alcohol 260 The above forms a limpid solution suitable for a printing ink base. At 70 F. it is stable and non-gelling for a period sumclently long to permit a reasonable time of storage before use.

Example 10 of 28% ammonia ture heated to about 169 dispersed. The resulting This is an ink base.

An ink is made by adding 20 parts of pulp blue to 25 parts of the above ink base and uniformly dispersing the pigmen The resulting ink dries Example 11 parts of com 50 tially all the prolamine has been removed, 10

Example 12 A volatile amine ink base is made by using:

Parts by weight F. until the protein is The solution has a pH of and again heat at 185 completely dispersed. 8.5, and is an ink base.

An ink is made from said base by dissolving 12 parts of a water-soluble blue dye in 50 parts of water. The dye solution is added to 400 parts of the ink base, and thoroughly incorporated therein. The, ink when printed on paper is nonsniudsinl. when given a short heat-treatment as in Example 6, it produces a bleed-proof ink.

The invention is not limited to claims.

I claim:

1. A printing ink containing ticles in suspension hicle comprising alkaline-soap-dispersed corn protein in an aqueous medium, the corn protein pigmentary particles in suspension in a fluid vehicle, said vehicle comprising alkaline-soap-dispersed corn protein having a pH not over 10.

5. A printing ink containing plgmentary particles in suspension in a fluid vehicle, said vehicle solution which acts as a lin solution, said in a fluid vehicle, said veuble soap, and said vehicle including in addition to its aqueous ingredient at least one volatile organic liquid miscible with water and liaving a pH not over 10." 2

7. A printing ink containing pigmentary particles in suspension in a fluid vehicle, said vehicle comprising alkaline-soap-dispersed gluten-pro teins of corn in an aqueous medium, the corn protein being free from a history of dispersing contact with an alkaline aqueous solution having a pH over 11, and buffering material for an alkaline solution which acts as a wetting agent in alkaline solution, said material including watersoluble soap, and said vehicle having a pH not over 10 said vehicle having a pH 'not over 10.

9. Aprinting ink containing pigmentary' particles in suspension in a fluid vehicle, said vehicle com risin alkaline-soap-dispersed gluten-progluten,

vehicle, a solution of zein in tein'which is companion to said zein in corn gluten. I

11. A printing ink containing as its essential a solvent liquid having an organic liquid solvent component, said solution containing in dispersion therein the protein content of the corn gluten from which gluten the said zein derived.

,12. A printing ink containing as its essential vehicle, a solution of zein in'i'i solvent liquid having an organic liquid solvent componen said solution containing in dispersion therein a corn protein which is companion to said zein in corn said dispersed protein being dyed to act as a pigmentary filler.

13. The method of making a printing ink base which comprises subjecting corn gluten tothe action of a solvent for the zein content oi! the gluten, whereby to form azein solutioncontainteins of corn in an aqueous medium, the corn protein being free from a history of dispersing contact with an alkaline aqueous solution having a pH over 11, and a rosin soap soluble in said medium whereby it acts as a buffer and a wetting agent, said vehicle having a pH not over 10.

10. A printing ink containing as its essential vehicle, a solution of zein in a solvent liquid having an organic liquid solvent component, said sotherein acorn pro lution containing in dispersion ed with said gluten is dispersed by ing the companion protein content 0! said gluten in a dispersed for 14. The method of making a printing ink base which comprises subjecting corn gluten to the action of a liquid printing-ink vehicle which is a volatile aqueous organic solvent for the zein content of the gluten in thepresence of dispersing alkali in said solvent, whereby the -zein is dissolved and the protein of the gluten associatalkali. v

15. A printing ink base comprisinga liquid vehicle and homogeneously distributed throughout said vehicle the proteins of corn gluten, said vehicle being volatile to the extent of leaving a solid residue ofcorn protein. r

' HARRY M. WEBER.

action of the 

